This is an ongoing project so I will update it later but background
For my physics class I have to construct and fire a trebuchet. My group was fortunate enough to be sponsored by EP minerals so we already had a trebuchet, as my teacher does this every year. However each year you have to change something on it. Last year the arm on our trebuchet was badly damaged, so this year we hacked it off and started on changing it drastically. Well sort of.
I don't have before pictures but here are some since we removed the old arm.
The frame
The original arm used 2 pieces of 2" box tubing stacked and welded and then those slid into two pieces of channel that sanwiched the arm. The channel had a rod welded through it which is the pivot. On the other end of the channel hung weights of choice. Which were able to freely swing.
We removed the box tubing and welded a piece of pipe directly onto the channel.
:one of my partners
Here I am messing around
The pipe is a little flexy since it is round and obviously lacks the rigidness of a square. So, we are going to put triangles onto the pipe and run a cable to one end of the pipe to the channel. We are going to do this on top and bottom.
We are going to increase the length of the channel by adding another 3.5' or so and then sandwhich 120lbs (rough estimate) liner plates from a gaint kiln used to bake DE. We plan on using 6 of these plates for roughly 700+ pounds.
Combined with the increased leverage and fixed weights (vs freely hung) We think this will be good to launch a 5 lbs pumpkin at least 3/4 across a football field. Or I hope. In the past they used closer to 900 lbs.
We're also adding new bearings and a hand crank to pull down the arm and we will introduce a new release for the arm.
I need to get some more recent pictures but theres a start and I just thought some of you might find this cool.
Ooo and the best part perhaps is that we have to wear costumes (as this is going on near Halloween ) and so we are dressing up as soldiers. My partner, (above in the picture) his brother just got back from Iraq and is going to lend us some of his ACU's or BDU's or whatever he has. Then, we have to fire at a target and hopefully hit it (we get to move it around, but consistency is key here). The target is a large piece of plywood propped up on pvc legs, she wants us to decorate it so I rasterbated a giant image of osama bin laden and we will glue it to our target
hehe
-Max
Edit: btw that CSM shirt is blasphemy because I'm admitted to Makay at UNR wooo
For my physics class I have to construct and fire a trebuchet. My group was fortunate enough to be sponsored by EP minerals so we already had a trebuchet, as my teacher does this every year. However each year you have to change something on it. Last year the arm on our trebuchet was badly damaged, so this year we hacked it off and started on changing it drastically. Well sort of.
I don't have before pictures but here are some since we removed the old arm.
The frame
The original arm used 2 pieces of 2" box tubing stacked and welded and then those slid into two pieces of channel that sanwiched the arm. The channel had a rod welded through it which is the pivot. On the other end of the channel hung weights of choice. Which were able to freely swing.
We removed the box tubing and welded a piece of pipe directly onto the channel.
:one of my partners
Here I am messing around
The pipe is a little flexy since it is round and obviously lacks the rigidness of a square. So, we are going to put triangles onto the pipe and run a cable to one end of the pipe to the channel. We are going to do this on top and bottom.
We are going to increase the length of the channel by adding another 3.5' or so and then sandwhich 120lbs (rough estimate) liner plates from a gaint kiln used to bake DE. We plan on using 6 of these plates for roughly 700+ pounds.
Combined with the increased leverage and fixed weights (vs freely hung) We think this will be good to launch a 5 lbs pumpkin at least 3/4 across a football field. Or I hope. In the past they used closer to 900 lbs.
We're also adding new bearings and a hand crank to pull down the arm and we will introduce a new release for the arm.
I need to get some more recent pictures but theres a start and I just thought some of you might find this cool.
Ooo and the best part perhaps is that we have to wear costumes (as this is going on near Halloween ) and so we are dressing up as soldiers. My partner, (above in the picture) his brother just got back from Iraq and is going to lend us some of his ACU's or BDU's or whatever he has. Then, we have to fire at a target and hopefully hit it (we get to move it around, but consistency is key here). The target is a large piece of plywood propped up on pvc legs, she wants us to decorate it so I rasterbated a giant image of osama bin laden and we will glue it to our target
hehe
-Max
Edit: btw that CSM shirt is blasphemy because I'm admitted to Makay at UNR wooo
I'm sure I will though. As far as the angle I'm not sure, we're cutting some triangles out so that the cable can "ride" in a notch on the top of them. Turnbuckles, exactly! We're also using one to adjust the rod where the sling hooks onto. 
hah
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